Field of Technology
The present disclosure generally relates to methods for refining steels and other alloys.
Description of the Background of the Technology
Argon-oxygen decarburization (“AOD”) is a secondary refining process used to decarburize molten alloys. AOD may reduce the carbon content of the molten alloys to a desired level. As applied to ferrous alloys, conventional AOD may generally comprise preparing a melt of a ferrous alloy, transferring the molten alloy to a suitable refining vessel, and injecting a mixture of argon and oxygen gases into the molten alloy through tuyeres. Contacting the molten alloy with the mixture of argon and oxygen gases may generate iron oxide (FeO) and carbon monoxide (CO). The argon may reduce the partial pressure of CO in the gas in contact with the molten alloy and result in preferential oxidation of carbon instead of chromium in molten stainless steel alloys. In this way, the carbon content of the melt may be reduced. The CO and argon injected through the tuyeres may also remove nitrogen from the molten alloy. The efficiency of carbon removal may be influenced by molten alloy composition, original carbon content of the alloy, composition of oxidizing gases, flow rates and temperatures of the injected gases, furnace condition (including size, geometry, and wear condition of the vessel), heat size, and initial and final temperatures of the molten alloy.
AOD and other conventional methods for decarburizing molten alloys may be time-consuming and/or expensive. It would be advantageous to provide improved methods for decarburizing molten alloys.